碳纳米管场发射电子源  

Electron source for carbon nanotube field emission

作　　者：薛增泉[1] 王晶云[1] 梁学磊[1] 罗骥[1] 张耿民[1] 张兆祥[1] 申自勇[1] 侯士敏[1] 赵兴钰[1] 张琦锋[1] 高崧[1] 吴锦雷[1] 

机构地区：[1]北京大学电子学系纳米器件物理及化学实验室,北京100871

出　　处：《真空》2005年第4期1-4,共4页Vacuum

基　　金：国家自然科学基金(60231010;6037100;69902002;90206048;50202001;50202002;60171025);973项目(2001CB610503)的资助

摘　　要：从实验和理论上研究单根碳纳米管(CNT)场发射电子源的稳定问题。利用透射电镜/扫描探针显微镜(TEM/SPM)和场发射显微镜/场离子显微镜(FEM/F IM)对CNT s的场发射特性进行了实验研究。同时从密度泛函理论出发,利用相关程序模拟计算了吸附对单壁碳纳米管(SW NT s)场发射的影响。发现SW NT s荷电体系的总能量与荷电电荷数量关系具有抛物线形式,先减小,达到最小值,之后增加。通常荷4个电子时达到最小值,即体系处于最稳定状态。表明SW NT s有很大的电负性,是容易发生凝聚和吸附分子的根源。进而计算了对氢、氧和水的吸附特性,讨论了吸附对场发射的影响。这些结果对CNT s的场发射特性和作为新型电子源的应用都是有重要意义的。The stability of the electron source for single carbon nanotube (CNT) field emission was studied theoretically and experimentally. The field emission properties of the invited CNT were experimentally investigated by the transition electron microscopy and scanning probe microscopy (TEM-SPM) as well as the field emission microscopy and field ion microscopy (FEM-FIM). In addition, the effects of gas adsorbed on SWNTs were computed simulatively on the basis of density functional theory. It was found that the relationship between the total energy of SWNT system and number of charges is in form of an upward concave parabolic curve on which usually the total energy reaches minimum if four electrons were charged, ie., the system is in a most stable state. This behavior shows that SWNTs possess much higher negativity that is just the root reason why it is easy to coagulate and adsorb gas molecules. Further, the adsorption properties of H, H_2O and O on SWNT were calculated with the effect of adsorption on SWCNT field emission discussed. The results mentioned above are of significance to the applications of field emission properties of CNTs as a new electron source.

关 键 词：碳纳米管 场发射 稳定性 

分 类 号：O484[理学—固体物理]